Summary of Significant Accounting Policies - Additional Information (Detail) $ in Thousands	12 Months Ended
Dec. 31, 2023 USD ($) item segment	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Basis of Presentation [Line Items]
Prepaid R&D expense	$ 7,245	$ 15,188
Expected dividend yield	0.00%	0.00%	0.00%
Unrecognized tax provisions	$ 0	$ 0
Unrecognized tax benefits, related interest and penalties	$ 0	$ 0
Number of operating segments \| segment	1
CSL Vifor and CKDP Agreements [Member] \| License and milestone fees
Basis of Presentation [Line Items]
Number of performance obligations for revenue recognized \| item	1
Prior to Regulatory Approval [Member]
Basis of Presentation [Line Items]
Cost of goods sold			$ 0
Employee Stock Option [Member]
Basis of Presentation [Line Items]
Expected life of options (in years)	6 years 3 months	6 years 3 months	6 years 3 months
Expected dividend yield	0.00%	0.00%	0.00%

Number of performance obligations for revenue recognized.

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Amount of asset related to consideration paid in advance for research and development expenses that provide economic benefits within a future period of one year or the normal operating cycle, if longer.

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Summary Of Significant Accounting Policies [Line Items]

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The aggregate costs related to goods produced and sold and services rendered by an entity during the reporting period. This excludes costs incurred during the reporting period related to financial services rendered and other revenue generating activities.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 924
-SubTopic 10
-Name Accounting Standards Codification
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Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of unrecognized tax benefits.

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Amount of expense for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

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